Apparatus for manufacturing dipped rubber articles



Sept 7, 1943. J. M Auzm- '2,328,769

APPARATUS FKOR MANUFACTURING DIPPED RUBBER ARTICLES Filed Nov. 27, 1959 Patented Sept. 7, 1943 APPARATUS FOR MANUFACTURING DEPPED RUBBER'ARTICLES John M. Auzin, Warwick, R. I., assigner to Davol Rubber Company, a corporation of Rhode Island Application November 27, 1939, Serial No. 366,222

(Cl. 1S--1l1)l 2 Claims.

My present invention relates to the manufacture of hollow rubber articles, and has particular reference to novel expansion forms therefor.

It is the principal object of my invention to' provide an improved expansion form for manufacturing rubber articles of hollow type.

t is a further object of my invention to manu facture hollow rubber articles of any desired shape, in a simple and inexpensive manner.

Another object of my invention is tomanu` facture hollow rubber articles by dipping.

With the above and other objects and advantageous Vfeatures in View,` my invention consists of a novel method and a novel apparatus,

`more fully described in the detailed description following, in conjunction with the accompanying drawing,4 and more speciiically denned in the claims appended thereto.

In the drawing: i

Fig. l is a plan View, partly broken away, showing a finished rubber article of hollow construction made in accordance with my invention;

Fig. 2` is a perspective view of an expansion form for use in manufacturing hollow rubber articles;

Fig. 3 is a sectional view showing the arrangement of parts for manufacturing hollow rubber articles by dipping;

Fig. 4 is a sectional detail of a modified arrangement; and

Fig. 5 is a View thereof with the parts arranged for the dipping operation.

It has been found desirable to provide an expansion form for the manufacture of hollow articles by dipping in a coating with a suitable material in solution, as for example latex or other suitable rubber solution or a solution of a material such as cellulose acetate or nitrate or the like, the form itself being of'an expansible material, such as for example rubber, whereby the form may be blown to suitable size and then used as a form for dipping into or for spraying with the solution, to provide a hollow layer of material over the entire form; the hollow layer may then be cured, hardened, and the expansible form collapsed for removal from the formed hollow article, which retains its initial shape. This arrangement thus provides a simple and effective method for forming hollow articles of any desired contour and shape, by using an expansion form which is blown to attain the desired inner dimensions of the hollow article, thus permitting formation of the hollow article by dipping into or by spraying with a solution of suitable material, the

blown form being subsequently collapsed and removed.

Referring to the drawing, ahollow rubber article such as avball Ill may be cheaply manufactured by using 'a preformed expansion form such as shown in Fig. 2. The form II `is preferably formed of an elongated rubber tube, which may be closed at one end if desired or may be open at both ends and which has a plurality of yheavy or less resilient bands I2 of rubber or the like spaced apart as indicated in Fig. 2. The form may be of dipped or molded rubber material, and is adapted to be mounted on a metal tube I3, see Fig. 3, which has a central bore I4 and a plurality of fluid outlet openings I5, the end being closed as with a cap I6 which is iitted with a tube I'I equipped with a valve IG'for admitting fluid,

,such as air, under pressure to the tube I3. When the rubber form is mounted on the metal tube I3, rubber clamps being placed ateach end ifV desired, and iluid under pressure is admitted to the interior thereof, the fluid expands the center portion of the rubber former as indicated in Fig. A3, the heavy relatively non-resilient bands I2, however, tightly gripping the form to the metal tube I3 so as to present an intermediate expanded surface as illustrated. The entire surface of the form is initially treated with a chemical adhesion preventing material, such as for example with a bromine or a chlorine solution such as disclosed in R'aiche Patent No. 2,043,630, whereby the form disclosed in Fig. 3 may be coated by dipping into a bath of latex or if preferred spraying with latex or other rubber in solution without any adherence to the form. A coating of rubber is thus obtained on the outer surface of the blown form, it being preferred to alternately dip the form into the rubber solution and into a coagulating solution until the desired thickness of outer layer is provided. The pressure fluid is then released from the dipped form by opening the valve I8, and the latex layer is cured; the metal and rubber forms are thenwithdrawn from the cured outer layer,`

which is then leached for an extended time depending upon the thickness of the rubber, preferably in hot water, in order to remove water soluble proteins from the rubber. The hollow article is then dried and trimmed for the necessary ttings.

When dipping a hollow `ball such as shown in Fig. 1, I have found that immersion of the blown rubber form into a latex or other rubber solution results in a slight tendency to collapse due to the pressure of the solution; but the removal of the dipped form between successive dips and for dipping in the coagulating solution permits an expansion of the air within the form to cure any partial collapse, and to again restore the form to its original blown form. The size of the blown form is controlled byusing standard length and width gauges to check the expanded size. The shape of the outer layer may also be changed after partly dIiyin'gQa-byf removing the shapediarticle from the form and" shaping, as for example flattening the bottom of a bulb, before nal drying, curing and leaching.

Any desired shape of hollowiarticl'e .'maybe made by using a rub-ber form of thepropen'shape, as indicated for example in Figsml and l5, which show a suitable arrangementforublowing"abll having a closed end. The rubber 'tube "form 'l9 is shown as slipped over a metal tube 20 which has air ducts 2| in the sides-and also int'he.-'end,

so that the blown up form assumes thefposi-tion shown-in Fig. 5. If it be preferred that one side of theiblowni article havefafgreaterltaperxthanathe other side, this can be readily accomplishedrzby shapingitheband '|21' onr'one side so asfto'iprovide aizg'rfadualfslope ifor :the dorm when tlisfblown'iup, :instead fof*1a11'fabrupt; turnias shown: ini Eigli.

other :suitable iaarange'ment may .Ocon- Y"vienientlymade; tot `o btain a thollnwxar tielemffsde Ii'fsired f contour 1f erfexample 'theJl-formlmawf deyfsired, fbezfleft :inzfthe i edrnipletdearticleinwhibh "ease-.the :form sneed) not be. treated ixvith aan'. adlrhesionipreventing material.

IThe :above-described;-arrangement provid'eslaJ A:simple riand Aeffe'etive manufacturing procedure --for obtaining holiowiaiti'cles at-ilowfleost,ias'the 'lifeiofftheform' continues iforS-a longtimemritil flits? resilience isA impaired. certain lioliowear-ti- Y. les. niayfifldesiied,` i permanentlyiretainiltheblaslitio' form` forffsu'eh feonstfrudtions, it is prferred #to Ctreat the -f-sur-faee fof` the f -relasticiformivvithiian f adhesivefm'aterial orfby 4using Ianiadhesive-1iin'a- R40 @terial ifoiitlieiforin'7 material. 'Ifi1u-s a latex-remi, {ifwit is not eurfaeevtreatedand"'ifiit is suineifently -dry, will fbeeome-iiritegrabwith the applied Aeater -m which is shaped to operating size and shape by "means of fluid pressure, and preferably by air (pressure.

.lZcclaim:

1. A device for manufacturing hollow rubber '1'1'5"artielesbydippirlgfcomprising an elongated fluid conduithavngaifluid inlet at one end and closed at the opposite en'fd, a hollow rubber form mountfedtof'envelopa 'substantial portion of said conduit .including said opposite end, means sealing '20 said 'form to said conduit to provide a closed --xzh'amber about ithe nizelopediportiuniof .said e'ortduit;: anda means'fieomprising.'ventsiterm'eliate Lthetiends :of `Lthe@conduit and floeatedfin lthe portioncofrthelzonduit:enveloped :by .rsaid Trubber admitting uid :under :..pressurefito #expand :the Aform.

L2... A device.'A for s-manufaetur'ing lhollowf rubber artielesrbyldipping, i comprising.an(l elongatedfuid .-30 c'onduitihavingf'afuidl i'rilet at oneiendand-'closed at the.oppositeiendga1hdllowlrubberiform=mount ved to -envelopua substantial portion #of-'said conrduit including said opposite -"en"d, -means sealing 'the 'ends-oi said x"fo'1-mto sai'dconduit -to 'provide T35 la elosedehamberlabout fthe-envelopedlportionlf fsaid conduit. and vmeans -fconiprising v-vents fin-ter- :mediate theff ends .i 'of-l-the. conduit and located"in the portion of the conduitfenvel'opedby lsai'd rubber form and positioned inthef'elosed'chamberibe'tween 'the sealedfends thereof,` for admitting iluid :under pressure i-to expand the-form.

'SJOHN fIvI.- AUZIN. 

